KEY POINTS
- An industrial powder coating line is a chain of stations: loading → pretreatment → dry-off → powder application → curing → cooling → unloading, connected by a conveyor and run from a PLC.
- Every station is sized from the same four inputs: the largest part, the required output, the conveyor speed, and the finish or certification target.
- Many quality problems (poor adhesion, uneven film, under-cure) can be traced to a station that was sized in isolation from the others.
When a factory asks for a "powder coating machine", what it usually needs is a powder coating line: a set of stations that clean the metal, apply the powder, cure it, and move parts through the whole sequence at a steady rate. This guide walks through each station in the order a part meets it. It also explains the decisions that shape each one.
1. Loading area and hangers
Parts are hung on hooks, jigs or racks attached to the conveyor. How you hang a part decides how many fit per metre of conveyor, where hanging marks will appear, and whether the powder reaches recesses. Aluminium extrusions on a vertical line hang from one end. On a horizontal line they hang lengthways, usually several profiles to a jig. Hanger design is worth settling early because it sets the real throughput of the line.
2. Surface pretreatment
Pretreatment removes oil, oxide and contamination and leaves a conversion layer that the powder bonds to. Ying Group lines use 3 to 7 stage spray tunnels: degreasing, rinsing, etching or deoxidising, conversion coating, and final rinses. The conversion chemistry can be chrome-based or chrome-free. The right number of stages depends on the substrate, the corrosion target and the certification required. Our pretreatment guide covers this station in detail.
3. Dry-off oven
After the final rinse, parts must be completely dry before they enter the booth. Trapped water causes blistering and adhesion failures. The dry-off oven is a hot-air tunnel sized around line speed, part mass and the chosen heating source (gas, electric or diesel). The parts also need to cool enough before spraying.
4. Powder coating booth
The booth contains the spray zone and controls airflow so powder that misses the part is captured instead of escaping into the plant. Booths can be manual, automatic, or built for fast colour change. A factory running many colours per shift needs a different booth than one running a single RAL colour all week.
5. Automatic guns, reciprocators and robots
Automatic guns on reciprocators move up and down (or in and out) so that film thickness stays consistent along the whole part. Manual touch-up stations handle recesses and corners. On complex profiles, gun positioning or robotic spraying makes film build repeatable across shifts and operators.
6. Powder recovery
Overspray is collected by cartridge filters, a cyclone, or both. In a cartridge-filter booth nearly all overspray goes back to the gun hopper, which suits long runs in one colour, but colour changes take longer because powder has to be cleaned out of the filters. A cyclone separates reusable powder from the air and is quick to clean, with an after-filter catching the fine dust, so it suits plants that change colour often. Recovery design directly affects powder consumption, which is one of the largest running costs of a line.
7. Curing oven
The curing oven melts the powder, lets it flow, and cross-links it. What matters is the temperature the metal itself reaches and how long it stays there, which is not the same as the air temperature. Ying Group ovens operate in the 180–220 °C range and are adjusted to the powder specification. Oven length is driven by conveyor speed and required dwell time; see how to size a curing oven.
8. Cooling and unloading
Parts leave the oven hot. A cooling zone, either natural or forced air, brings them to a temperature where they can be inspected, unloaded and packed without marking the fresh coating.
9. Conveyor
The conveyor ties every station together. A continuous monorail moves everything at one speed. A power & free conveyor lets carriers stop, buffer and switch routes, which helps with heavy parts or mixed products. The trade-offs are covered in power & free vs. monorail.
10. PLC and HMI controls
A PLC with a touchscreen HMI runs conveyor speed, temperatures, pretreatment pumps and dosing, booth airflow and alarms. Ying Group lines ship with Siemens or Schneider Electric hardware and remote diagnostics. SCADA is available for multi-line plants. Stored recipes let operators switch products without re-tuning the line by hand.
How the stations are sized together
| Input | What it drives |
|---|---|
| Largest part (L × W × H, weight) | Tunnel and oven cross-section, booth opening, conveyor load rating, hanger design |
| Required output | Conveyor speed and hanging density, therefore the length of every tunnel and oven |
| Finish / certification target | Number of pretreatment stages, chemistry, film thickness, cure window |
| Colour changes per day | Booth type and powder recovery design |
| Floor space and building height | Line layout (straight, U-shape, multi-pass oven), vertical vs. horizontal |
| Available utilities | Heating source for ovens and pretreatment tanks |
This is why a good quotation starts with questions, not a price list. Ying Group engineers every line around the customer's product, floor plan and utilities, then builds it at our DECO-PRO machinery plant in Shiyan, Hubei. Our own technical team installs and commissions it on site.
Frequently asked questions
What are the main parts of a powder coating line?
A complete line has a loading area, surface pretreatment, a dry-off oven, a powder booth with guns and powder recovery, a curing oven, a cooling zone, an unloading area, a conveyor connecting all stations, and a PLC/HMI control system.
Is a powder coating booth enough on its own?
For small job shops a standalone booth and batch oven can work. For production volumes, the parts must be pretreated, dried, coated and cured in a controlled sequence, which needs a connected line with a conveyor.
What temperature does a powder coating curing oven run at?
Typical curing ovens run between 180 and 220 °C. What matters is the metal temperature and how long the part stays at it, which must match the powder manufacturer's cure schedule.
How long does it take to build and install a powder coating line?
It depends on the line size and scope. Ying Group confirms the schedule after the layout review, covering engineering, manufacturing, shipping, installation and commissioning.